Revert "Add a Danger check to prevent review approval for cops that have become Enabled: true"

It was not a good solution for us. Also CI fails unintentionally. So we are going to revert it.

This reverts commit c9723aa.

Author: ydah

.github/workflows/danger.yml

@@ -5,7 +5,6 @@ source 'https://rubygems.org'
 gemspec
 
 gem 'bump'
-gem 'danger'
 gem 'rack'
 gem 'rake'
 gem 'rspec', '~> 3.11'